The present invention relates to the field of joint sealants. In particular, the present invention provides a novel compressible sealant with hydrophilic properties.
The principle function of a joint sealant is to prevent the entry of water into the space between adjacent structural elements. The structural elements may be pairs of a building, roadway, parking deck, bridge, or other engineering structure. They may be fixed relative to one another, or fairly mobile relative to one another. Waterproofing a joint between two relatively immobile elements is fairly straight forward, because fairly inflexible material can be utilized. However, even then, thermal expansion and contraction of the joint must be considered. Mobile joints, like expansion joints in bridge surfaces present greater problems, because they are expected to flex in three dimensions, and joints exposed to standing water, such as those found in drainage systems, or canals, must exhibit enhanced water resistance, as well as flexibility in many applications.
Flexible, water resistant joint sealants have taken several forms. For instance, in Emseal Corporation""s COLORSEAL(trademark) and BACKERSEAL(trademark) products, sealants composed of alternate layers of compressible and incompressible foam are utilized. Such sealants provide the flexibility inherent in compressible, usually impregnated forms and the moisture resistance of incompressible, closed cell foams. A limitation of such products is that under severe moisture conditions, or when exposed to standing water, moisture can penetrate between the foam layers.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.
On the other hand, hydrophilic sealants, that expand to form a water tight plug when exposed to moisture, are also available. The drawback of these is that they are relatively inflexible, so generally have been found to be inappropriate for use in mobile joints.
In a broad aspect, the present invention relates to a joint seal for use in joints that may be exposed to water comprising at least one layer of a compressible impregnated open cell foam, on at least a portion of the surface of which is positioned a hydrophilic material.
The object of the present invention is to provide a joint sealant that combines the best properties of compressible foam and hydrophilic sealants. The sealant of the present invention is flexible enough to be used in mobile joints, and upon exposure to water will expand to firmly seal a joint.